SARS-CoV-2 reinfection after previous infection and vaccine breakthrough infection through the second wave of pandemic in India: An observational study.

BACKGROUND: There are sparse longitudinal data on SARS-CoV-2 infection after previous infection and after partial or full vaccination. METHODS: This study of a cohort of healthcare workers used Kaplan-Meier analysis with appropriate definition of events and censoring and used Cox models to assess outcomes, with data cut-off on June 18, 2021. RESULTS: A total of 1806 individuals with median age of 32 (18-64) years, 1483 (82.1%) with at least one vaccine dose, 1085 (60.1%) with 2 vaccine doses, 408 (22.6%) with at least one episode of SARS-CoV-2 infection, and 6 (1.47%) with 2 episodes of infection were included in the analysis. At median follow-up of 38.4 weeks after first SARS-CoV-2 infection (n=408), the 52-week probability of reinfection was 2.2% (95% CI, 1.0-4.91%); and at median follow-up of 13.3 weeks after second dose, the 16-week probability of breakthrough infection was 5.6% (95% CI, 4.33-7.23%), which was significantly higher among those without previous SARS-CoV-2 infection versus with previous infection (6.4% vs 1.8%, p=0.016, adjusted Cox HR=3.49, 95% CI, 1.09-11.20, p=0.036) and females versus males (7.9% vs 3.8%, p=0.007, adjusted Cox HR=2.06, 95% CI 1.19-3.56, p=0.01). CONCLUSIONS: There was low probability of reinfection after previous SARS-CoV-2 infection and higher vaccine breakthrough infections among females and those without previous infection.

Improved survival among oral cancer patients: findings from a retrospective study at a tertiary care cancer centre in rural Kerala, India.

BACKGROUND: Oral cancer is very common in India. The reported 5-year survival of such patients is around 50% after treatment with surgery and radiotherapy, much lower than most of the developed countries. METHODS: A retrospective study of a prospective database of oral cancer patients undergoing surgery from June 2009 to June 2013 was conducted. Follow-up details were updated from case records and by phone calls. Data were double entered in EpiData Entry version 3.1 and were analysed using EpiData Analysis software 2.1.0.73. RESULTS: Two-hundred and twenty patients were analysed (136 males); 85% were consuming tobacco, mainly in chewable form. The majority (51.1%) had tongue cancer, of whom 75 patients (34.1%) had T4 tumours. Postoperative radiotherapy was given to 108 patients (49.1%). Forty had recurrence, of which 23 were in early stage. Of these, 19 showed node positivity (p < 0.01). Node-negative patients had 79% 5-year survival while node positive had 59% which is comparable to that reported in developed countries. Median disease-free survival duration was 48.2 months. CONCLUSIONS: Node positivity is the single factor affecting recurrence and survival. The overall survival and disease-free survival is better in patients without lymph node involvement and in patients with early stage of cancer as compared to the patients with node involvement and in advanced stages.